The present invention relates to a control apparatus of an engine having a cylinder into which a piston is reciprocatably fitted.
Conventionally, in order to improve fuel consumption of an engine, it is desirable to reduce a loss caused by release of thermal energy of combustion gas from a wall surface of a combustion chamber to an outside of the engine, in other words, a cooling loss.
In this regard, for example, JP2013-194622A discloses an engine in which, within an engine operating range where an engine load is low, an air layer is formed around an outer circumferential region of a combustion chamber by causing fuel to stagnate within a center region of the combustion chamber, so as to reduce by the air layer release of thermal energy of combustion gas to an outside of the engine.
According to the engine of JP2013-194622A, a cooling loss can be reduced and fuel consumption can be improved. However, with the engine, the cooling loss is only reduced within the operating range where the engine load is low, and the fuel consumption cannot sufficiently be improved.